Time-limit relay.



G. A. BURNHAM.

\ TIME LIMIT RELAY. APPLICATION FILED APR. 14, 1913. 1,230,063. Patented June 12, 1917.

2 SHEETSSHEET I.

nun X MMMM l g h MMMM WWWWI fivuenz'oz'r G. A. BURNHAM TIME LIMIT RELAY.

APPLICATION FILED APR. 14, 1913.

1,230,063. Patented June 12, 1917.

2 SHEETS-SHEET 2.

UNITED, STATES PATENT OFFICE.

GEORGE A, BURNHAM, OF-SAUGUS, MASSACHUSETTS, ASSIGNOR TO SEARS B.

- CONDIT, JR., BBOOKLINE, MASSACHUSETTS.

TIME-LIMIT RELAY.

Specification of Letters Patent. Patented June 12, 1917. i

. Application filed April 14, 1913. Serial No. 760,870.

' To all whomz't may concern:

Be it known that I, GEORGE A. BURNHAM, a citizen of the United States, residing at Saugus, in the county of Essex and State of Massachusetts, have invented an Improvement in Time-Limit Relays, of which the following is a specification.

This invention relates to time-limit relays for controlling electric circuits, and has for its object the embodiment-in a single apparatus, preferably in a single device, of an inverse and a definite type or form of time limit relay, said apparatus or device having means to operate a switch which is inversely responsive to overloads of different, current values up to a predetermined current value, and other means associated with the aforesaid means, arranged to operate a switch which is definitely responsive to overloads of higher current values, thus producing a time-limit relay which is selective. This result I accomplish by using the force of a solenoid to operate a switch against the resistance of a retarding device on moderate overloads, while on heavier overloads the force of the solenoid will compress a spring and thereafter the force of the spring will close the switch against the resistance of the retarding device. v

In the embodiment of my invention here shownfor the sake of illustration, a single device is employed involving a motor in the form of .a solenoid, which is responsive to an overload, a swltch-operating member moved by it, and a timing-element for regulatingthespeed of movement whereby the time consumed by it in operating is variable according to the current value of the overload up to a predetermined current value, and a spring'adapted to be compressed upon operation of the'solenoid when. responding to overloadsof higher current values, which is arrangedto move said switch-operating member at a uniform rate of speed so. that the time consumed by it in operating the switch is definite regardless of the current value ofthe overload.

The invention also has for its object the I construction of the several parts, which,

when combined produce a selective timelimit relay and embodying both the inverse and the definite timing features, but which may be modified and combined to produce a relay embodying the inverse timing feature only.

- condition to operate.

Fig. 3 is a front elevation of a time-limit device modified to embody only the inverse timing feature.

Fig. 4 is a longitudinal vertical section of the time-limit device of Fig. 3 taken on the dotted line 44.

Fig. 5 is a horizontal section of the timelimit device of Fig. 3, taken on the dotted line 5-5.

-Fig. 6 is a sectional detail of the timingelement.

Fig. 7 noid.

Fig. 8 is a modification illustrating a normally closed switch adapted to be opened by the switch-operating member.

Fig. 9 is a diagram of the time-limit device of Fig. 1 in a transformer circuit.

Fi 10 is a diagramof the time-limit device of Fig. 8 in a transformer circuit.

10 represents the inclosing-case for the relay. The relay-magnet; here shown as a solenoid, which serves as the motor, is constructed to especially adapt it for the present purpose, although it may be constructed in any usual or suitable manner. As repreis a horizontal section of thesolesented in Fig. 4, it is arranged on the bot 1 tom of thecase beneath an ear 14, which extends inwardly. It has four magnet-coils 12, arranged in series relation on the spool 13, or in lieu thereof one or more coils may be employed-as desired. A tube 15 of brass or other suitable materialis fitted in the bore ofthe spool, as a lining, and is extended throughoutthe lengthof the spool 27 and also projects below the lower end of the spool for a short distance, said lower pro-- at the upper end-portion of the core-piece 16, at the bottom of the reduced end-portion 17, bears against the under side of the. ear and the nut against the upper side of the ear,'thereby firmly attaching said stationary core-piece to the ear and thus holding the solenoid in place. The stationary core-piece extends but partially through the bore of the spool and its lower end is formed with a conical recess 19. Said stationary core-piece is also slotted from end to end at to form an air-passage. Said stationary core-piece has a center-hole through it which receives a longitudinally movable rod 23, with an inclosing tube 24 fixed thereto, the latter being extended throughout the length of the stationary core-piece and projecting a short distance below the lower end thereof. A movable core-piece 25 is arranged on said rod 23, within the tube 15, and is entirely I confined in said tube, and its upper end-portion is made conical to enter the conical recess in the lower end-portion of the stationary core-piece, when the solenoid is-energized. Said core-piece isislidably mounted on the rod and is pressedagainst the lower end of the tube 24 by a spring 26, encircling the rod and bearing at its upper end against the lower end of the core-piece and at its lower end against a thumb-nut 27, which is fixed to the lower end of the rod 23. The

movable core-piece is thus yieldingly supported on the rod yet admits of rotary move ment of the rod within it. As the upper end of the movable core-piece engages the lower end of, the tube 24 on the rod it will be seen that when current passes through the coils and said core-piece is moved the, rod will be moved by it in an upward direction until such movement is checked by the upper end of the movable core-piece striking against the lower end of the stationary core? piece. Downward movement of the movable core-piece is limited by a ring 28 fitted into and affixed to the lower end of the tube 15, against which said core-piece strikes on its downward movement. The movable core-piece is slotted longitudinally from end to end to form an air-passage like the stationary corepiece. The upper end-portion of the rod 23 is screw-threaded and passes through a threaded hole in a yoke 30, the arms of which are extended upward and are provided with trunnions 31 for pivotally connecting the same toa pair of parallel bars 32, at a point intermediate their length. Said yoke serves as a lever-support and said bars are rigidly connected together toform a lever, and, as here shown they are pivotally connected at one end to the opposite sides of a block 33, and at their otherends are connected together by a pin 34 which is extended transversely through them. The block 33 serves as a pivotal support for one end of the lever and the other end of the .der having a centerhole through it, through plvotally connected to an ear 37 on the case,

thus providing for a lateral movement of the block. The timing-element here shown consists of a hollow cylinder 40, closed at its lower end and open at its upper end, its lower closedend having a boss 41, through which a pivot-pin 42 extends for pivotally connecting the cylinder to an car 43 on the case. A piston 45 is contained in the cylinwhich extends the lower reduced end-portion of a'rod 46, which has a valve-formed end 47, adapted to engage a seating-portion 48, formed on the lower end of the piston around the center-hole. The valve-formed end 47 is closed on its seat upon longitudinal movement of the rod, and when closed on its seat the passage through the piston-is closed, but upon further movement of the rod in the same direction the piston will be moved by the rod in an upward direction, such movement being at a slow rate of speed. Said rod 46 also has a transversely arranged pin 49, above the piston which is adapted to engage, the top of the piston or the plate thereon upon downward movement of the rod, thereby to move the piston in an outward direction. The distance between the pin 49 and the valve-formed end of the rod is greater than the length of the piston, thus admitting of a slight independent movement of the rod, so that when the pin is in engagement with the top of the piston the valveformed end will be removed from its seat, 1 thus opening the passage through the pistonand admitting of a quickreturn movement. The upper end of the rod 46 is pivotally connected to the. lever 32, so that the piston is moved, by said lever, and in time regulates the speed of movement of said lever in one direction. Said lever has a transversely arranged pin 50, which serves as a, contactmember, for engaging a pair of resilient contact-members 51, 51, thereby to close a circuit. The resilient contact-members may be of any suitable construction, and are here shown as attached to a block 52 of insulating material which is supported in the case. The circuit controlled by the contact-member 50 and resilient contact-members 51, is normally open, but in case a closed circuit is desired the circuit-controller represented in Fig. 8 may be employed, wherein resilient contact-members 55, 55, are attached to a block and normally engaged by a springpressed contact-member 56, which is arranged in the path of movement of a pin 57 on the lever 32.

In the selective type of inverse time-limit relay shown in Figs. 1 and 2, the spring 38 is made quite long and is adapted to be compressed only on an overload of at least a predetermined value, as for instance, an overload equal to three times the full load yet said spring also serves as a cushion for the lever to prevent it from vibrating or chattering when the magnet-coil is influenced by an alternating current, which is an important feature. In the simple type of inverse time-limit relay shown in Figs. 3, 4 and 8, a short spring 38 is employed, which has but a slight yielding movement, just enough to enable the spring to serve as a cushion and prevent vibration. In the form shown in Fig. 1, upon the occurrence of light overloads the movable core-piece will respond and lift the lever 32 on its end-support as a pivot, its rate of speed depending upon and corresponding to the current value of the overload. Thus its movement is variable according to the current value of the overload. The slowly moving lever continues to move until its pin 50 engages the contact-members 51. Upon the occurrence of a heavy over load, or an overload suflicient to compress the springv 38, the movable core-piece will respond quickly, the lever'will be moved quickly, and its end-support will be moved to compress the spring 38, while the other endof the lever willrespond more slowly and will be moved by the expansion of said spring, which has just been compressed,- which exerts a uniform thrust, hence its rate 1 of speed is substantially constant according .to the force exerted by the spring as contrasted to being variable according to the value of the current. Thus on slight overloads the lever is moved at a variable speed according to the current value of the overload up to a predetermined value and consumes variable periods of time in closing the circuit and is moved at a definitespeed regardless of the current value of the overload on overloads of higher current value, and consumes adefiniteperiod of time in closing the circuit, thereby involving both the inverse and definite timing features. In

. the form shown in Figs. 3, 4 and 8 the movement of 'the lever 32 is variable according to the current value of the overload on overloads of all currentvalues, the spring merely serving as a cushion.

As .here shown, branch circuit-wires lead from the magnet-coils 12, as represented in Figs 8 and 9, wherein it will be seen that four branch circuit wires 60, lead from the four magnet-coils to stationary contact-members 61, with which a movable contact-meld ber '62 is adapted to cotiperate, thereby to include more or less of said wires in the transformer circuit, so that the coil of the solenoid may be adjusted by including a greater hence is not herein claimed.

I claim l. A selective time-limit device for controlling electric circuits comprising means to operate a switch which is inversely re--.

sponsive to overloads of different current values up to a predetermined current value and other means associated with the aforesaid means to operate the switch which is definitely responsive to overloads of higher current values only, substantially as described.

2. A selective time-limit device for controlling electric circuits comprising electromagnetically operated means to operate the switch, including a solenoid and a timingelement, inversely responsive to overloads of different current values up to a predetermined current value, and means associated with the aforesaid means and arranged to be set in condition for actuation by said solenoid only on overloads of higher current values, to operate the switch at the end of a definite period of time regardless of the current value of the overload, substantially as described.

3. A selective time-limit device for controlling electric circuits comprising electromagnetically operated means to operate'a switch including a solenoid and a timing element, inversely responsive to overloads of different current values up to a predetermined current value, and a spring arranged to be set in condition for actuation by said solenoid only on overloads of higher current values, and which operates the switch at the end of a definite period of time regardless of the current value of the overload, substantially as described.

4. In a time-limit controllin apparatus for electric circuits, the com ination of means variably responsible tooverloads of different current values up to a predeterapparatus 1 -mined current value for controlling the operation of a switch at the'end of correspondingly variable periods of time, and other means operated by the aforesaid means 5 only upon overloads of higher current values, for controlling the operation 'of the switch at the end of a definite period of time regardless of the current value of the overload, substantially as described.

6. In a time-limit controlling apparatus for electric circuits, the combination of means variably'responsive to overloads of different current values up to a predetermined current value for controlling the operation of a switch at the end of correspondingly variable periods of time, and a spring energizedin response to overloads of higher current values only, for controlling the operation of the switch at the end of a definite period of time,.regardle ss of the current value of the overload, substantially as described. I g I 7. In a time-limit controlling apparatus for electric circuits, the combination of means variably responsive to overloads of different current values up to a predetermined current value for controlling the operation of a switch at the end of correspondingly variable periods'of time, and a ospring energized by the aforesaid variably responsive means on overloads of higher current values which controls the operation of theswitch at the endof a definite period of time regardless of the current value of the overload, substantially as described.

I 8. A selective time-limit device comprising a movable switch-operating member, a timing-device .for regulating its speed of motion, means for imparting'to said mein-. '40 ber a variable thrust accordlng to the cur rent value of an overload up to a predetermined current value, and means associated with the aforesaid means for imparting to said member a uniform thrust regardless of the current value of an overload on overloads of higher current values, substantially as described v e 9. A selective time-limit device comprising a movable switch-operating member, a timing-device for regulating its speed of motion, electro-responsive means for imparting tosaid member a variable thrust according to'the current value of an overload up to a predetermined current value, and means associated with the aforesaid means and arranged for actuation thereby for maintainin a uniform thrust on said member regard ess of the current value of an overload on overloads of higher current values, substantially asdescribed.

1 0. A selective time-limit device comprising a movable switch-operating member, a

timing-device for regulating its speed of motion, electro-responsive means for impartmg to said member a variable thrust accordment connected with it, a spring engaging it,

- pressed acting tov move said member' at a I ment connected with one end of said mem- -up to a predetermined current value and 120 parting a uniform movement to said mem-- 'ber regardless of-the current value of the 125 'bination a-solenoid having a movable core ing a movable switch-operating member, a

timing-device to regulate its speed of mo tion, electro-responsive means for imparting to said member a variable thrust according to the current value of an overload up to a predetermined current value, and a spring adapted to be compressed by said means 30 on overloadsof higher current values which imparts to said member a uniform thrust regardless of the current value of the overload, substantially as described. 1 12. A selective time-limit device compris ing a movable switch-operating member, ,a timing-device to regulate its speed of motion, electro-re sponsive means for imparting to said member avariable thrust according to the-current value of an overload up to a predetermined current value, and a spring engaging said minber and adapted to be compressed by a movement of said member on overloads of higher current values which imparts to. said member a uniform thrust 're- 5 gardless of the current value of the overload,-substantially as described. 13. In a selective time-limit relay, a movable switch-operating member, a timing-elemeans responsive to an overload for moving said member to operate a switch at a speed which is variable according to the current value of the overload up to a predetermined current value and for moving said memberto 1 5 compress said spring on overloads of higher current values, and said spring when comuniform rate of speed regardless of the current value of the overload to operate the switch, substantially as described.

14. In a selective time-limit relay, a pivoted switch-operating member, a timing eleber, a spring engaging the opposite end of said member, means responsive to an overload for moving said member to operate the switch at a speed which is variable according to the current value. of the overload for moving said member to compress'said spring on overloads of higher current values, said spring when compressed 1m overload, substantially as described.

15. A time-limit relay comprising in compiece, a rod carrying said core-piece, a leversupport arranged on said rod, a lever plvot- 'said' block is slidably arranged, a

ally connected to said support at a point intermediate its length, a timing-element connected with one end of said lever, a yielding support to which the other end of said lever is pivoted, a contact-member borne by said lever and a stationary contact-member into'and out of engagement with which the aforesaid contact-member is movable, substantially-as described.

16. A time-limit relay comprising in combination a solenoid having astationary corepiece and a movable core-piece, a rod carrying said movable core-piece, a lever-support adjustably arranged on said rod, a lever pivotally connected to said support at a point intermediate its length a timing-element connected with one end of said lever, a yielding support to which the other end of said leveris pivoted, a contact-member borne by said lever, and a stationary contact-member into and out of engagement with which the aforesaid contact-member is movable, substantially as described.

17. A time-limit relay comprising in combination a solenoid having a stationary core-pieceand a movable core-piece, a rod carrying said movable core-piece, a leversupport adjustably arranged on said rod, a lever pivotally connected to said support at a point intermediate its length, a pivotally supported timing-element connected with one end of said lever, a block to which the other end of said lever is pivotally connected, a pivotally supported stem on which spring bearing upon the block, a contact-member borne by said lever and a stationary contact-member into and out of engagement with which the aforesaid contact-member is movable, substantially as described.

18. A time-limit relay comprising in combination a solenoid'having a stationary corepiece and a movable core-piece, a rod carrying said movable core-piece, said rod being rotatable and having a screw threaded end-portion, a lever-support arranged on the screw threaded portion of said rod, a lever pivotally connected to said support at a point intermediate its length, a timingelement connected with one-end of said lever, a yielding support to which the other end of said lever is pivoted, a contact-member borne by said lever, and another contact member into and out of engagement with which the aforesaid contact-member is movable, substantially as described.

19. A selective time-limit device for controlling electric circuits comprising electromagnetically operated means to operate a switch including a solenoid and a timingelement, inversely responsive to overloads of different current values up to a predetermined current value, and a spring arranged to be set in condition for actuation by said solenoid only on overloads of higher current values, and which operates the switch at the end of a definite period of time regardless of the current value of'the overload, and means to adjust said spring thereby to vary its setting, substantially as de scribed.

20. A selective time-limit device comprising a movable switch-operating member, means for adjusting it to vary the distance moved by it to operate the switch, a timingdevice for regulating its speed of motion, means for imparting to said member a va riable thrust according to the current value of an overload up to a predetermined current value, and means associated with the aforesaid means for imparting to said member a uniform thrust regardless of the current value of an. overload on overloads of higher current values, substantially as described;

In testimony whereof I have signed my' name to this specification, in the presence of two subscribin witnesses.

GE RGE A. BURNHAM.

Witnesses:

D. M. SHIFFERT, H. U. CALDER. 

